This invention relates to gas recovery and is more specifically concerned with the recovery of gases from enclosures containing equipment which has to operate in a gaseous environment other than air.
There are many areas of technology in which fairly large equipment is required to operate in an atmosphere of a particular gas. One such area is the electrical supply industry where, for example, electric circuit breakers are often required to operate in an atmosphere of sulphur hexafluoride (SF.sub.6) gas.
Sulphur hexafluoride gas is relatively expensive and it is normally recovered and stored if equipment which normally works in the gas is to be serviced or repaired. As the equipment may be sited in remote areas, a portable assembly is used to recover the gas and to recharge the equipment with the gas after the equipment has been serviced or repaired. Such assembly comprises a large pump and a storage vessel normally mounted on a vehicle. The amount of gas to be recovered may be 200 kg or more, and, as it is normally at pressures between 4 and perhaps 20 atmospheres in the enclosure, the pump used must have a high capacity and the assembly is therefore a cumbersome and expensive piece of equipment, which is used only intermittently.